Why aren't there any fireflies in California?

June 16, 2009

I've lived in Ohio, Michigan, Mississippi, North Carolina, and Maryland, but I've been a resident of southern California for 12 years. I noticed almost instantly the first time we hit the summer months here that the Golden State has no lightning bugs (fireflies)? Why?

(My friends back east say that fireflies aren't as commonly seen there as they used to be. Are fireflies disappearing? Yes, I see this question has been posed before, but the answer wasn't really satisfactory. Are you part of the disappearing firefly conspiracy? Is this some type of campaign by the mayonnaise manufacturers – reduce the number of fireflies to increase demand, then bring them back and simultaneously jack up the price of mayo jars? Maybe it's related to the honeybee disappearance too?)

—Gumbypiz, Long Beach

SDSTAFF Doug replies:

Sorry our earlier discussion left you thinking something's fishy. As far as California's missing fireflies go, it's got nothing to do with conspiracies, climate change, disappearing bees, or anything else. There are fireflies in California. However:

1. Since (a) fireflies feed exclusively on snails in damp habitats, and (b) most of California is lacking in native snails in damp habitats, there aren't a lot of places you can find fireflies. When you do find them, it's generally not in large numbers.

2. Most Californian fireflies (e.g., Ellychnia) happen not to be bioluminescent. It's just a different assemblage of species from the ones on the east coast.

3. In the California firefly species that are bioluminescent, the organs in question are pretty dim and hard to notice, unlike their eastern U.S. counterparts, which glow a bright yellow green. Also, these particular critters live in places where people are unlikely to see them to begin with.

In other words, you can find fireflies in California if you go out of your way and know where and when to look. But most Californians either are never going to see them or won't notice them when they do.

—DougStraight Dope Science Advisory Board

Staff Reports are written by the Straight Dope Science Advisory Board, Cecil's online auxiliary. Though the SDSAB does its best, these columns are edited by Ed Zotti, not Cecil, so accuracywise you'd better keep your fingers crossed.